1) 6x + 10 = 5x and 2) –2x = 4?

You put like terms on the same side of the equals sign, but when you do that, you change the plus to a minus or the minus to a plus. Then you solve for the unknown x:

6x + 10 = 5x

6x + 10 = +5x So you change the sign to a minus when it

changes its position on the other side of the

equation

6x – 5x = -10 Then 10 changes its sign also

x = -10

PROOF (substitute answer for x):

6(-10) + 10 = 5(-10)

-60 +10 = -50

-50 = -50

You do the same for the second equation but now you have to divide each side by -2 to get x by itself on one side of the equation:

-2x = 4

-2x/-2 = 4/-2 Remember, two minuses when divided, are a plus

x = -2

PROOF:

-2x = 4

-2(-2) = 4 Remember, two minuses multiplied equals a plus

4 = 4

10 = 5x – 6x

then simplify:

10 = -x

but remember that you are looking for x. what we obtained earlier was -x, which indicates that x has a coefficient of -1. to isolate x, we have to divide both sides by -1, and we get:

-10 = x

2) -2x = 4

same thing with the last step in 1). the goal is to find x, which has a coefficient of -2. divide both sides by -2, and we get:

x = -2